ICDcodes.org
FY2027

S44.0 vs S54.0

S44.0 and S54.0 can never be reported together. ICD-10-CM declares them mutually exclusive with an Excludes1 note, meaning the two conditions cannot occur in the same patient — so exactly one of them is correct for any given encounter.

The official note, declared on S44.0
ulnar nerve NOS (S54.0)
S44.0

Injury of ulnar nerve at upper arm level

Not billable
Chapter 19
Injury, poisoning and certain other consequences of external causes
Section
S40-S49
Indexed under
  • Injury › nerve NEC › ulnar › arm
S54.0

Injury of ulnar nerve at forearm level

Not billable
Chapter 19
Injury, poisoning and certain other consequences of external causes
Section
S50-S59
Use when the record says
  • Injury of ulnar nerve NOS
Indexed under
  • Injury › nerve NEC › ulnar

Excludes1 is not always absolute: where two conditions covered by the note are genuinely unrelated, CMS guidance permits reporting both. Document the reasoning rather than assuming it. More on Excludes1 vs Excludes2 · FY2027